Noradrenaline In Rat Brain Research Articles

Influence of drugs on the temperature-lowering effect of harmaline

Harmaline (30 mg/kg), injected intraperitoneally into rats, causes a decrease in body temperature. Treatment with either α-methyl-dopa (200 mg/kg, i.p.) or with a-methyltyrosine (200 mg/kg, i.p.) 24 hr before, or with p-chlorophenylalanine (315 mg/kg, i.p.) 72 hr before injection of haarmaline, did not influence the decrease in temperature. Reserpine (5 mg/kg, i.p.) given 24 hr before harmaline did not affect the temperature fall caused by the latter drug. However, administration of Ro-4-4602 (693 mg/kg, i.p.), an inhibitor of dopa decarboxylase, or sodium diethyldithiocarbamate (360 mg/kg, i.p.) 24 hr after reserpine and 1 hr before the injection of harmaline prevented the fall in temperature ( p <0.05). Administration of harman (25 mg/kg), and harmalol (28 mg/kg), two derivatives of harmaline, also caused a fail in body temperature. The compounds harmaline, harman and harmalol, all antagonized the action of serotonin on the rat uterus. Distribution between free and bound serotonin and free and bound noradrenaline in rat brain (omitting the cerebellum), 1or 2 hr after the administration of harmaline, did not differ significantly from that observed in brains of saline-teeated controls. The results suggest that the decrease in body temperature after the administration of harmaline may be the consequence of a disturbance of monoamine relationship at brain thermoreceptor sites.

The inhibitory effect of eight neuroleptic drugs (butyrophenones and phenothiazines) on the rat brain noradrenaline increase produced by tranylcypromine

The inhibitory effects of eight neuroleptics (six butyrophenones and two phenothiazines) on the penetration of noradrenaline from cytoplasm into intracellular granules in rat brain were investigated. Four of them are potent inhibitors of this phenomenon. The results suggest that, from a physico-chemical point of view, there are two classes of neuroleptics, class I acting primarily at the intracellular granular membrane level, class II primarily at the whole cell membrane level.

Influence of four butyrophenone neuroleptics on rat brain noradrenaline depletory effect of reserpine

Four potent butyrophenone neuroleptics, haloperidol, spiroperidol, droperidol and benperidol fail to counteract the rat brain noradrenaline depletory effect of reserpine. These observations lead to the conclusion that the inhibition of the action of reserpine by certain neuroleptics is a non specific property.